Monday, June 06, 2016

Racing - Sprinting By The (Power) Numbers

This is related to my jump/sprint numbers from the other night.

Me getting led out at the now defunct SUNY Purchase Tuesday Night Sprints, probably 1991 or so.

My good friend and former teammate sent me a link to this interesting sprinting article: "The Profile Of A Sprint" from The Science of Sport website. It's a great article, opening with one of those bike cams mounted on a couple pros' bikes (on the Giant team). Go ahead, watch it, I'll wait.

Clip from above linked article.

Okay, so that was exciting, right? Really chaotic, and, frankly, it's really difficult for me to tell when the rider should jump. I guess that's why they have markers every 100 meters for the last kilometer (or more), because if I were in such a sprint I'd have one eyeball on them and another on the riders around me.

I'll sort of follow along their article and inject some of my own thoughts.

Sprint Length

First, they state that a pro sprint typically lasts about 10-15 seconds at the end of typically flatter (and therefore less selective) stages, allowing for a large number of riders to arrive at the finish together. I'd want to add here that for at least the Tour de France, the Champs Elysee stage seems to end up being a much longer sprint. One winter I studied a number of stage sprints while on the trainer and found that most sprints were short, like 10-13 pedal revs in the wind. This is well under 10 seconds in the wind.

A notable exception? The Champs consistently seemed to be 20 revs or so, or almost twice that of a "regular" stage. Not having every sprinted on the Champs I can't tell you exactly why this is the case, but I'm guessing it has to do with the wind (tailwind?), the slight down hill nature of the finish, and the fact that it's a super prestigious stage for a sprinter to win so they'll go a bit earlier.

Good Sprinters are Good Sprinters

What's really interesting is that in the Grand Tours from 2008 to 2011 there were 79 field sprints. 54 of those sprints were won by 5 riders. 19 others accounted for the remaining 25 sprints. This means that there were really just 5 really effective sprinters for those years. That's a very, very, very small number.

Power Numbers

Now for some nitty gritty - wattage and speed. What's incredible is that the power numbers aren't out of this world. For the six sprinters studied the average peak power was about 1250w, a number that even I can hit.

Sustained power, for the average 13 second sprint, was about 1020w. Again, this is a totally attainable number by a number of riders, me included.

My "good" sprints have been about 1250w peak with the best sprint being a sustained 1100w effort for 18 or 19 seconds. Typically my peak will be about that, like 1250w, but depending on the sprint my sustained effort is usually shorter and usually is in the 1050w range.

Top speed averaged about 41 mph. That's fast but not outlandishly fast.

Basically even the best pros are sprinting at numbers you might see in a Cat 3 race.

Of course there's a huge difference between the pros and a Cat 3. Cat 3s aren't racing for 3-6 hours before the sprint, they don't have a massively fast (and tough) final hour, and they typically don't have to hold 30+ mph before they get into the sprint.


I think that the numbers only tell part of the story. Obviously hitting the numbers counts. But reaching the end of the race in good position, with as much in reserve as possible, is critical. I'm sure there are much stronger sprinters out there that don't get the job done regularly, and there are weaker sprinters out there doing super well. Race craft counts for a lot, but it's good to know what sort of numbers the big boys are hitting. At least it's a point of reference.

No comments: